Originally Posted by stf92
(http://www.diyaudio.com/forums/multi-way/195410-8-ohms-woofer-plus-4-ohms-tweeter.html#post2687607)

Hi: suppose I want to make a speaker with an 8 ohms woofer and a 4 ohms tweeter. Would this be reasonable? That would be all.

Tell us your reasons, and we'll tell you if it's "reasonable."

borispm

27th August 2011 06:18 AM

Hi stf92,
There are quite a number of designs that have 8 ohm woofer and 4 ohm tweeters. If your amp can handle 4 ohm loads properly, you're fine.

The impedance fluctuation of dynamic drivers, especially woofers, are quite huge. Some drivers may be rated at 8 ohm but their impedance rises to say 50ohm at high frequency and that's all right. Your mileage may vary but I would say matching a 4 ohm tweeter to an 8 ohm woofer is reasonable.

stf92

27th August 2011 06:56 AM

Thanks for your kind reply. The amp will be a TDA7294 integrated circuit. I was just looking for the data sheets I keep in my desk, and do not find them. I'll look at the web.

I think what matters is the amp output impedance vs freq, although I do not think such a curve will be in the data sheets. Well, you've given me the fundamental advice: amp must be able to drive 4 ohms. Thanks a lot.

planet10

27th August 2011 07:49 AM

Quote:

Originally Posted by borispm
(http://www.diyaudio.com/forums/showthread.php?p=2687657#post2687657)

Hi stf92,
There are quite a number of designs that have 8 ohm woofer and 4 ohm tweeters. If your amp can handle 4 ohm loads properly,

And probably as many with 4 ohm woofer(s) and 8 ohm tweeters.

dave

stf92

27th August 2011 08:07 AM

A curious statement on circuits, in particular about crossovers.

Hi: This statement refers to a circuit you'll be able to see here. The rightmost branch, that containing C3, I will cut it so we are speaking of the series combination of C2, R3 and VC3. For all I know from circuit analysis, any permutation of those three components, for instance R3, C2, VC3 won't make any difference at any point in the circuit.

But, as is logical, I acknowledge there are people who knows more than I do. Can somebody tell me whether I am wrong?